So assuming he bought the entire 29 calculators he would've spent:
[tex]29 \times 3.85 = 111.65[/tex]
That leaves him with,
[tex]200 - 111.65 = 88.35[/tex]
Looking back at the prices i'm assuming there is no way he can reach 99 calculators with what he has left, so i will establish an equation that defines the number of calculators he can buy with the remaining £88.35.
Let c be the number of calculators he can still buy. Note that we are working in the 30-99 range so each calculator costs £3.65
[tex]88.35 = 3.65c[/tex]
[tex]c = \frac{88.35}{3.65} = 24.2[/tex]
So now we know he can still buy 24 calculators in addition to the 29 calculators, so in total he bought,
[tex]29 + 24 = 53[/tex]
Your answer would be 53 calculators.
What about the 0.2 remaining 'calculators',well that would be left over money which aren't sufficient to purchase an additional calculator+we were working with the 30-99 range meaning each one costs £3.65
[tex]0.2 \times 3.65 = 0.73[/tex]
So he bought 53 calculators and has 0.73£ remaining.
Hope this helps :)
